<template>
  <!-- Root element of PhotoSwipe. Must have class pswp. -->
  <div class="pswp" tabindex="-1" role="dialog" aria-hidden="true">
    <!-- Background of PhotoSwipe.
         It's a separate element as animating opacity is faster than rgba(). -->
    <div class="pswp__bg"></div>
    <!-- Slides wrapper with overflow:hidden. -->
    <div class="pswp__scroll-wrap">
      <!-- Container that holds slides.
        PhotoSwipe keeps only 3 of them in the DOM to save memory.
        Don't modify these 3 pswp__item elements, data is added later on. -->
      <div class="pswp__container">
        <div class="pswp__item"></div>
        <div class="pswp__item"></div>
        <div class="pswp__item"></div>
      </div>
      <!-- Default (PhotoSwipeUI_Default) interface on top of sliding area. Can be changed. -->
      <div class="pswp__ui pswp__ui--hidden">
        <div class="pswp__top-bar">
          <!--  Controls are self-explanatory. Order can be changed. -->
          <div class="pswp__counter"></div>
          <slot name="button-after"></slot>
          <button class="pswp__button pswp__button--close" title="Close (Esc)"></button>
          <button class="pswp__button pswp__button--share" title="Share"></button>
          <button class="pswp__button pswp__button--fs" title="Toggle fullscreen"></button>
          <button class="pswp__button pswp__button--zoom" title="Zoom in/out"></button>
          <slot name="button-before"></slot>
          <!-- Preloader demo http://codepen.io/dimsemenov/pen/yyBWoR -->
          <!-- element will get class pswp__preloader--active when preloader is running -->
          <div class="pswp__preloader">
            <div class="pswp__preloader__icn">
              <div class="pswp__preloader__cut">
                <div class="pswp__preloader__donut"></div>
              </div>
            </div>
          </div>
        </div>
        <div class="pswp__share-modal pswp__share-modal--hidden pswp__single-tap">
          <div class="pswp__share-tooltip"></div>
        </div>
        <button class="pswp__button pswp__button--arrow--left" title="Previous (arrow left)"></button>
        <button class="pswp__button pswp__button--arrow--right" title="Next (arrow right)"></button>
        <div class="pswp__caption">
          <div class="pswp__caption__center"></div>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
  import PhotoSwipe from 'photoswipe/dist/photoswipe'
  import UI from 'photoswipe/dist/photoswipe-ui-default'
  import objectAssign from 'object-assign'
  import Loading from '../../../components/tsui/loading'

  export default {
    name: 'previewer',
    computed: {
      imgs() {
        return this.list.map(one => {
          if (!one.msrc) {
            one.msrc = one.src
          }
          if (typeof one.w === 'undefined') {
            one.w = 0
            one.h = 0
          }
          return one
        })
      }
    },
    methods: {
      init(index) {
        const self = this
        let showItem = this.imgs[index]
        if (!showItem) showItem = {};
        if (!showItem.w || !showItem.h || showItem.w < 5 || showItem.h < 5) {
          const img = new Image()
          Loading.open();
          img.onload = function () {
            Loading.close()
            showItem.w = this.width
            showItem.h = this.height
            self.doInit(index)
          }
          img.src = showItem.src
        } else {
          this.doInit(index)
        }
      },
      doInit(index) {
        const self = this
        let options = objectAssign({
          history: false,
          shareEl: false,
          tapToClose: true,
          index: index
        }, this.options)
        this.photoswipe = new PhotoSwipe(this.$el, UI, this.imgs, options)
        this.photoswipe.listen('gettingData', function (index, item) {
          if (!item.w || !item.h || item.w < 1 || item.h < 1) {
            const img = new Image();
            Loading.open();
            img.onload = function () {
              Loading.close()
              item.w = this.width
              item.h = this.height
              self.photoswipe.updateSize(true)
            }
            img.src = item.src
          }
        })
        this.photoswipe.init()
        this.photoswipe.listen('close', () => {
          this.$emit('on-close')
        })
      },
      show(index) {
        this.init(index)
      },
      getCurrentIndex() {
        return this.photoswipe.getCurrentIndex()
      },
      close() {
        this.photoswipe.close()
      },
      goTo(index) {
        this.photoswipe.goTo(index)
      },
      prev() {
        this.photoswipe.prev()
      },
      next() {
        this.photoswipe.next()
      }
    },
    props: {
      list: {
        type: Array,
        required: true
      },
      index: {
        type: Number,
        default: 0
      },
      options: {
        type: Object,
        default() {
          return {}
        }
      }
    }
  }
</script>

<style>
  @import '~photoswipe/dist/photoswipe.css';
  @import '~photoswipe/dist/default-skin/default-skin.css';
</style>
